2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2000 Wim Taymans <wtay@chello.be>
5 * gstbuffer.c: Buffer operations
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Library General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Library General Public License for more details.
17 * You should have received a copy of the GNU Library General Public
18 * License along with this library; if not, write to the
19 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
20 * Boston, MA 02111-1307, USA.
25 * @short_description: Data-passing buffer type, supporting sub-buffers.
26 * @see_also: #GstPad, #GstMiniObject
28 * Buffers are the basic unit of data transfer in GStreamer. The #GstBuffer
29 * type provides all the state necessary to define a region of memory as part
30 * of a stream. Sub-buffers are also supported, allowing a smaller region of a
31 * buffer to become its own buffer, with mechanisms in place to ensure that
32 * neither memory space goes away prematurely.
34 * Buffers are usually created with gst_buffer_new(). After a buffer has been
35 * created one will typically allocate memory for it and set the size of the
36 * buffer data. The following example creates a buffer that can hold a given
37 * video frame with a given width, height and bits per plane.
39 * <title>Creating a buffer for a video frame</title>
42 * gint size, width, height, bpp;
44 * size = width * height * bpp;
45 * buffer = gst_buffer_new ();
46 * GST_BUFFER_SIZE (buffer) = size;
47 * GST_BUFFER_MALLOCDATA (buffer) = g_malloc (size);
48 * GST_BUFFER_DATA (buffer) = GST_BUFFER_MALLOCDATA (buffer);
53 * Alternatively, use gst_buffer_new_and_alloc()
54 * to create a buffer with preallocated data of a given size.
56 * The data pointed to by the buffer can be retrieved with the GST_BUFFER_DATA()
57 * macro. The size of the data can be found with GST_BUFFER_SIZE(). For buffers
58 * of size 0, the data pointer is undefined (usually NULL) and should never be used.
60 * If an element knows what pad you will push the buffer out on, it should use
61 * gst_pad_alloc_buffer() instead to create a buffer. This allows downstream
62 * elements to provide special buffers to write in, like hardware buffers.
64 * A buffer has a pointer to a #GstCaps describing the media type of the data
65 * in the buffer. Attach caps to the buffer with gst_buffer_set_caps(); this
66 * is typically done before pushing out a buffer using gst_pad_push() so that
67 * the downstream element knows the type of the buffer.
69 * A buffer will usually have a timestamp, and a duration, but neither of these
70 * are guaranteed (they may be set to #GST_CLOCK_TIME_NONE). Whenever a
71 * meaningful value can be given for these, they should be set. The timestamp
72 * and duration are measured in nanoseconds (they are #GstClockTime values).
74 * A buffer can also have one or both of a start and an end offset. These are
75 * media-type specific. For video buffers, the start offset will generally be
76 * the frame number. For audio buffers, it will be the number of samples
77 * produced so far. For compressed data, it could be the byte offset in a
78 * source or destination file. Likewise, the end offset will be the offset of
79 * the end of the buffer. These can only be meaningfully interpreted if you
80 * know the media type of the buffer (the #GstCaps set on it). Either or both
81 * can be set to #GST_BUFFER_OFFSET_NONE.
83 * gst_buffer_ref() is used to increase the refcount of a buffer. This must be
84 * done when you want to keep a handle to the buffer after pushing it to the
87 * To efficiently create a smaller buffer out of an existing one, you can
88 * use gst_buffer_create_sub().
90 * If a plug-in wants to modify the buffer data in-place, it should first obtain
91 * a buffer that is safe to modify by using gst_buffer_make_writable(). This
92 * function is optimized so that a copy will only be made when it is necessary.
94 * A plugin that only wishes to modify the metadata of a buffer, such as the
95 * offset, timestamp or caps, should use gst_buffer_make_metadata_writable(),
96 * which will create a subbuffer of the original buffer to ensure the caller
97 * has sole ownership, and not copy the buffer data.
99 * Several flags of the buffer can be set and unset with the
100 * GST_BUFFER_FLAG_SET() and GST_BUFFER_FLAG_UNSET() macros. Use
101 * GST_BUFFER_FLAG_IS_SET() to test if a certain #GstBufferFlag is set.
103 * Buffers can be efficiently merged into a larger buffer with
104 * gst_buffer_merge() and gst_buffer_span() if the gst_buffer_is_span_fast()
105 * function returns TRUE.
107 * An element should either unref the buffer or push it out on a src pad
108 * using gst_pad_push() (see #GstPad).
110 * Buffers are usually freed by unreffing them with gst_buffer_unref(). When
111 * the refcount drops to 0, any data pointed to by GST_BUFFER_MALLOCDATA() will
114 * Last reviewed on August 11th, 2006 (0.10.10)
116 #include "gst_private.h"
118 #include "gstbuffer.h"
120 #include "gstutils.h"
121 #include "gstminiobject.h"
123 static void gst_buffer_init (GTypeInstance * instance, gpointer g_class);
124 static void gst_buffer_class_init (gpointer g_class, gpointer class_data);
125 static void gst_buffer_finalize (GstBuffer * buffer);
126 static GstBuffer *_gst_buffer_copy (GstBuffer * buffer);
127 static GType gst_subbuffer_get_type (void);
129 static GType _gst_subbuffer_type = 0;
130 static GType _gst_buffer_type = 0;
133 _gst_buffer_initialize (void)
137 gst_buffer_get_type ();
138 gst_subbuffer_get_type ();
140 /* the GstMiniObject types need to be class_ref'd once before it can be
141 * done from multiple threads;
142 * see http://bugzilla.gnome.org/show_bug.cgi?id=304551 */
143 ptr = g_type_class_ref (GST_TYPE_BUFFER);
144 g_type_class_unref (ptr);
145 ptr = g_type_class_ref (_gst_subbuffer_type);
146 g_type_class_unref (ptr);
150 gst_buffer_get_type (void)
152 if (G_UNLIKELY (_gst_buffer_type == 0)) {
153 static const GTypeInfo buffer_info = {
154 sizeof (GstBufferClass),
157 gst_buffer_class_init,
166 _gst_buffer_type = g_type_register_static (GST_TYPE_MINI_OBJECT,
167 "GstBuffer", &buffer_info, 0);
169 return _gst_buffer_type;
173 gst_buffer_class_init (gpointer g_class, gpointer class_data)
175 GstBufferClass *buffer_class = GST_BUFFER_CLASS (g_class);
177 buffer_class->mini_object_class.copy =
178 (GstMiniObjectCopyFunction) _gst_buffer_copy;
179 buffer_class->mini_object_class.finalize =
180 (GstMiniObjectFinalizeFunction) gst_buffer_finalize;
185 gst_buffer_finalize (GstBuffer * buffer)
187 g_return_if_fail (buffer != NULL);
189 GST_CAT_LOG (GST_CAT_BUFFER, "finalize %p", buffer);
192 g_free (buffer->malloc_data);
194 gst_caps_replace (&GST_BUFFER_CAPS (buffer), NULL);
197 memset (buffer, 0xff, sizeof (GstBuffer));
202 * gst_buffer_copy_metadata:
203 * @dest: a destination #GstBuffer
204 * @src: a source #GstBuffer
205 * @flags: flags indicating what metadata fields should be copied.
207 * Copies the metadata from @src into @dest. The data, size and mallocdata
208 * fields are not copied.
210 * @flags indicate which fields will be copied. Use #GST_BUFFER_COPY_ALL to copy
211 * all the metadata fields.
213 * This function is typically called from a custom buffer copy function after
214 * creating @dest and setting the data, size, mallocdata.
219 gst_buffer_copy_metadata (GstBuffer * dest, const GstBuffer * src,
220 GstBufferCopyFlags flags)
222 g_return_if_fail (dest != NULL);
223 g_return_if_fail (src != NULL);
225 GST_CAT_LOG (GST_CAT_BUFFER, "copy %p to %p", src, dest);
227 if (flags & GST_BUFFER_COPY_FLAGS) {
230 /* copy relevant flags */
231 mask = GST_BUFFER_FLAG_PREROLL | GST_BUFFER_FLAG_IN_CAPS |
232 GST_BUFFER_FLAG_DELTA_UNIT | GST_BUFFER_FLAG_DISCONT |
234 GST_MINI_OBJECT_FLAGS (dest) |= GST_MINI_OBJECT_FLAGS (src) & mask;
237 if (flags & GST_BUFFER_COPY_TIMESTAMPS) {
238 GST_BUFFER_TIMESTAMP (dest) = GST_BUFFER_TIMESTAMP (src);
239 GST_BUFFER_DURATION (dest) = GST_BUFFER_DURATION (src);
240 GST_BUFFER_OFFSET (dest) = GST_BUFFER_OFFSET (src);
241 GST_BUFFER_OFFSET_END (dest) = GST_BUFFER_OFFSET_END (src);
244 if (flags & GST_BUFFER_COPY_CAPS) {
245 if (GST_BUFFER_CAPS (src))
246 GST_BUFFER_CAPS (dest) = gst_caps_ref (GST_BUFFER_CAPS (src));
248 GST_BUFFER_CAPS (dest) = NULL;
253 _gst_buffer_copy (GstBuffer * buffer)
257 g_return_val_if_fail (buffer != NULL, NULL);
259 /* create a fresh new buffer */
260 copy = gst_buffer_new ();
262 /* we simply copy everything from our parent */
263 copy->data = g_memdup (buffer->data, buffer->size);
264 /* make sure it gets freed (even if the parent is subclassed, we return a
266 copy->malloc_data = copy->data;
267 copy->size = buffer->size;
269 gst_buffer_copy_metadata (copy, buffer, GST_BUFFER_COPY_ALL);
275 gst_buffer_init (GTypeInstance * instance, gpointer g_class)
279 buffer = (GstBuffer *) instance;
281 GST_CAT_LOG (GST_CAT_BUFFER, "init %p", buffer);
283 GST_BUFFER_TIMESTAMP (buffer) = GST_CLOCK_TIME_NONE;
284 GST_BUFFER_DURATION (buffer) = GST_CLOCK_TIME_NONE;
285 GST_BUFFER_OFFSET (buffer) = GST_BUFFER_OFFSET_NONE;
286 GST_BUFFER_OFFSET_END (buffer) = GST_BUFFER_OFFSET_NONE;
292 * Creates a newly allocated buffer without any data.
295 * Returns: the new #GstBuffer.
298 gst_buffer_new (void)
302 newbuf = (GstBuffer *) gst_mini_object_new (_gst_buffer_type);
304 GST_CAT_LOG (GST_CAT_BUFFER, "new %p", newbuf);
310 * gst_buffer_new_and_alloc:
311 * @size: the size of the new buffer's data.
313 * Creates a newly allocated buffer with data of the given size.
314 * The buffer memory is not cleared. If the requested amount of
315 * memory can't be allocated, the program will abort. Use
316 * gst_buffer_try_new_and_alloc() if you want to handle this case
317 * gracefully or have gotten the size to allocate from an untrusted
318 * source such as a media stream.
321 * Note that when @size == 0, the buffer data pointer will be NULL.
324 * Returns: the new #GstBuffer.
327 gst_buffer_new_and_alloc (guint size)
331 newbuf = gst_buffer_new ();
333 newbuf->malloc_data = g_malloc (size);
334 GST_BUFFER_DATA (newbuf) = newbuf->malloc_data;
335 GST_BUFFER_SIZE (newbuf) = size;
337 GST_CAT_LOG (GST_CAT_BUFFER, "new %p of size %d", newbuf, size);
343 * gst_buffer_try_new_and_alloc:
344 * @size: the size of the new buffer's data.
346 * Tries to create a newly allocated buffer with data of the given size. If
347 * the requested amount of memory can't be allocated, NULL will be returned.
348 * The buffer memory is not cleared.
350 * Note that when @size == 0, the buffer data pointer will be NULL.
354 * Returns: a new #GstBuffer, or NULL if the memory couldn't be allocated.
359 gst_buffer_try_new_and_alloc (guint size)
364 malloc_data = g_try_malloc (size);
366 if (G_UNLIKELY (malloc_data == NULL && size != 0)) {
367 GST_CAT_WARNING (GST_CAT_BUFFER, "failed to allocate %d bytes", size);
371 /* FIXME: there's no g_type_try_create_instance() in GObject yet, so this
372 * will still abort if a new GstBuffer structure can't be allocated */
373 newbuf = gst_buffer_new ();
375 GST_BUFFER_MALLOCDATA (newbuf) = malloc_data;
376 GST_BUFFER_DATA (newbuf) = malloc_data;
377 GST_BUFFER_SIZE (newbuf) = size;
379 GST_CAT_LOG (GST_CAT_BUFFER, "new %p of size %d", newbuf, size);
385 * gst_buffer_get_caps:
386 * @buffer: a #GstBuffer.
388 * Gets the media type of the buffer. This can be NULL if there
389 * is no media type attached to this buffer.
391 * Returns: a reference to the #GstCaps. unref after usage.
392 * Returns NULL if there were no caps on this buffer.
394 /* FIXME can we make this threadsafe without a lock on the buffer?
395 * We can use compare and swap and atomic reads. */
397 gst_buffer_get_caps (GstBuffer * buffer)
401 g_return_val_if_fail (buffer != NULL, NULL);
403 ret = GST_BUFFER_CAPS (buffer);
412 * gst_buffer_set_caps:
413 * @buffer: a #GstBuffer.
416 * Sets the media type on the buffer. The refcount of the caps will
417 * be increased and any previous caps on the buffer will be
420 /* FIXME can we make this threadsafe without a lock on the buffer?
421 * We can use compare and swap and atomic reads. Another idea is to
422 * not attach the caps to the buffer but use an event to signal a caps
425 gst_buffer_set_caps (GstBuffer * buffer, GstCaps * caps)
427 g_return_if_fail (buffer != NULL);
429 gst_caps_replace (&GST_BUFFER_CAPS (buffer), caps);
433 * gst_buffer_is_metadata_writable:
436 * Similar to gst_buffer_is_writable, but this only ensures that the
437 * refcount of the buffer is 1, indicating that the caller is the sole
438 * owner and can change the buffer metadata, such as caps and timestamps.
440 * Returns: TRUE if the metadata is writable.
443 gst_buffer_is_metadata_writable (GstBuffer * buf)
445 return (GST_MINI_OBJECT_REFCOUNT_VALUE (GST_MINI_OBJECT_CAST (buf)) == 1);
449 * gst_buffer_make_metadata_writable:
452 * Similar to gst_buffer_make_writable, but does not ensure that the buffer
453 * data array is writable. Instead, this just ensures that the returned buffer
454 * is solely owned by the caller, by creating a subbuffer of the original
455 * buffer if necessary.
457 * After calling this function, @buf should not be referenced anymore. The
458 * result of this function has guaranteed writable metadata.
460 * Returns: A new #GstBuffer with writable metadata.
463 gst_buffer_make_metadata_writable (GstBuffer * buf)
467 if (gst_buffer_is_metadata_writable (buf)) {
470 ret = gst_buffer_create_sub (buf, 0, GST_BUFFER_SIZE (buf));
472 /* copy all the flags except IN_CAPS */
473 GST_BUFFER_FLAGS (ret) = GST_BUFFER_FLAGS (buf);
474 GST_BUFFER_FLAG_UNSET (ret, GST_BUFFER_FLAG_IN_CAPS);
475 /* data should always be set to READONLY */
476 GST_BUFFER_FLAG_SET (ret, GST_BUFFER_FLAG_READONLY);
478 gst_buffer_unref (buf);
484 typedef struct _GstSubBuffer GstSubBuffer;
485 typedef struct _GstSubBufferClass GstSubBufferClass;
487 #define GST_IS_SUBBUFFER(obj) (G_TYPE_CHECK_INSTANCE_TYPE ((obj), _gst_subbuffer_type))
488 #define GST_SUBBUFFER_CAST(obj) ((GstSubBuffer *)(obj))
497 struct _GstSubBufferClass
499 GstBufferClass buffer_class;
502 static GstBufferClass *sub_parent_class;
504 static void gst_subbuffer_init (GTypeInstance * instance, gpointer g_class);
505 static void gst_subbuffer_class_init (gpointer g_class, gpointer class_data);
506 static void gst_subbuffer_finalize (GstSubBuffer * buffer);
509 gst_subbuffer_get_type (void)
511 if (G_UNLIKELY (_gst_subbuffer_type == 0)) {
512 static const GTypeInfo subbuffer_info = {
513 sizeof (GstSubBufferClass),
516 gst_subbuffer_class_init,
519 sizeof (GstSubBuffer),
525 _gst_subbuffer_type = g_type_register_static (GST_TYPE_BUFFER,
526 "GstSubBuffer", &subbuffer_info, 0);
528 return _gst_subbuffer_type;
532 gst_subbuffer_class_init (gpointer g_class, gpointer class_data)
534 GstBufferClass *buffer_class = GST_BUFFER_CLASS (g_class);
536 sub_parent_class = g_type_class_peek_parent (g_class);
538 buffer_class->mini_object_class.finalize =
539 (GstMiniObjectFinalizeFunction) gst_subbuffer_finalize;
543 gst_subbuffer_finalize (GstSubBuffer * buffer)
545 gst_buffer_unref (buffer->parent);
547 GST_MINI_OBJECT_CLASS (sub_parent_class)->
548 finalize (GST_MINI_OBJECT_CAST (buffer));
552 gst_subbuffer_init (GTypeInstance * instance, gpointer g_class)
554 GST_BUFFER_FLAG_SET (GST_BUFFER_CAST (instance), GST_BUFFER_FLAG_READONLY);
558 * gst_buffer_create_sub:
559 * @parent: a #GstBuffer.
560 * @offset: the offset into parent #GstBuffer at which the new sub-buffer
562 * @size: the size of the new #GstBuffer sub-buffer, in bytes.
564 * Creates a sub-buffer from @parent at @offset and @size.
565 * This sub-buffer uses the actual memory space of the parent buffer.
566 * This function will copy the offset and timestamp fields when the
567 * offset is 0. If not, they will be set to #GST_CLOCK_TIME_NONE and
568 * #GST_BUFFER_OFFSET_NONE.
569 * If @offset equals 0 and @size equals the total size of @buffer, the
570 * duration and offset end fields are also copied. If not they will be set
571 * to #GST_CLOCK_TIME_NONE and #GST_BUFFER_OFFSET_NONE.
574 * Returns: the new #GstBuffer.
575 * Returns NULL if the arguments were invalid.
578 gst_buffer_create_sub (GstBuffer * buffer, guint offset, guint size)
580 GstSubBuffer *subbuffer;
584 g_return_val_if_fail (buffer != NULL, NULL);
585 g_return_val_if_fail (buffer->mini_object.refcount > 0, NULL);
586 g_return_val_if_fail (buffer->size >= offset + size, NULL);
588 /* find real parent */
589 if (GST_IS_SUBBUFFER (buffer)) {
590 parent = GST_SUBBUFFER_CAST (buffer)->parent;
594 gst_buffer_ref (parent);
596 /* create the new buffer */
597 subbuffer = (GstSubBuffer *) gst_mini_object_new (_gst_subbuffer_type);
598 subbuffer->parent = parent;
600 GST_CAT_LOG (GST_CAT_BUFFER, "new subbuffer %p (parent %p)", subbuffer,
603 /* set the right values in the child */
604 GST_BUFFER_DATA (GST_BUFFER_CAST (subbuffer)) = buffer->data + offset;
605 GST_BUFFER_SIZE (GST_BUFFER_CAST (subbuffer)) = size;
607 /* we can copy the timestamp and offset if the new buffer starts at
610 GST_BUFFER_TIMESTAMP (subbuffer) = GST_BUFFER_TIMESTAMP (buffer);
611 GST_BUFFER_OFFSET (subbuffer) = GST_BUFFER_OFFSET (buffer);
612 complete = (buffer->size == size);
614 GST_BUFFER_TIMESTAMP (subbuffer) = GST_CLOCK_TIME_NONE;
615 GST_BUFFER_OFFSET (subbuffer) = GST_BUFFER_OFFSET_NONE;
622 /* if we copied the complete buffer we can copy the duration,
623 * offset_end and caps as well */
624 GST_BUFFER_DURATION (subbuffer) = GST_BUFFER_DURATION (buffer);
625 GST_BUFFER_OFFSET_END (subbuffer) = GST_BUFFER_OFFSET_END (buffer);
626 if ((caps = GST_BUFFER_CAPS (buffer)))
628 GST_BUFFER_CAPS (subbuffer) = caps;
630 GST_BUFFER_DURATION (subbuffer) = GST_CLOCK_TIME_NONE;
631 GST_BUFFER_OFFSET_END (subbuffer) = GST_BUFFER_OFFSET_NONE;
632 GST_BUFFER_CAPS (subbuffer) = NULL;
634 return GST_BUFFER_CAST (subbuffer);
638 * gst_buffer_is_span_fast:
639 * @buf1: the first #GstBuffer.
640 * @buf2: the second #GstBuffer.
642 * Determines whether a gst_buffer_span() can be done without copying
643 * the contents, that is, whether the data areas are contiguous sub-buffers of
647 * Returns: TRUE if the buffers are contiguous,
648 * FALSE if a copy would be required.
651 gst_buffer_is_span_fast (GstBuffer * buf1, GstBuffer * buf2)
653 g_return_val_if_fail (buf1 != NULL && buf2 != NULL, FALSE);
654 g_return_val_if_fail (buf1->mini_object.refcount > 0, FALSE);
655 g_return_val_if_fail (buf2->mini_object.refcount > 0, FALSE);
657 /* it's only fast if we have subbuffers of the same parent */
658 return (GST_IS_SUBBUFFER (buf1) &&
659 GST_IS_SUBBUFFER (buf2) &&
660 (GST_SUBBUFFER_CAST (buf1)->parent == GST_SUBBUFFER_CAST (buf2)->parent)
661 && ((buf1->data + buf1->size) == buf2->data));
666 * @buf1: the first source #GstBuffer to merge.
667 * @offset: the offset in the first buffer from where the new
668 * buffer should start.
669 * @buf2: the second source #GstBuffer to merge.
670 * @len: the total length of the new buffer.
672 * Creates a new buffer that consists of part of buf1 and buf2.
673 * Logically, buf1 and buf2 are concatenated into a single larger
674 * buffer, and a new buffer is created at the given offset inside
675 * this space, with a given length.
677 * If the two source buffers are children of the same larger buffer,
678 * and are contiguous, the new buffer will be a child of the shared
679 * parent, and thus no copying is necessary. you can use
680 * gst_buffer_is_span_fast() to determine if a memcpy will be needed.
683 * Returns: the new #GstBuffer that spans the two source buffers.
684 * Returns NULL if the arguments are invalid.
687 gst_buffer_span (GstBuffer * buf1, guint32 offset, GstBuffer * buf2,
692 g_return_val_if_fail (buf1 != NULL && buf2 != NULL, NULL);
693 g_return_val_if_fail (buf1->mini_object.refcount > 0, NULL);
694 g_return_val_if_fail (buf2->mini_object.refcount > 0, NULL);
695 g_return_val_if_fail (len > 0, NULL);
696 g_return_val_if_fail (len <= buf1->size + buf2->size - offset, NULL);
698 /* if the two buffers have the same parent and are adjacent */
699 if (gst_buffer_is_span_fast (buf1, buf2)) {
700 GstBuffer *parent = GST_SUBBUFFER_CAST (buf1)->parent;
702 /* we simply create a subbuffer of the common parent */
703 newbuf = gst_buffer_create_sub (parent,
704 buf1->data - parent->data + offset, len);
706 GST_CAT_DEBUG (GST_CAT_BUFFER,
707 "slow path taken while spanning buffers %p and %p", buf1, buf2);
708 /* otherwise we simply have to brute-force copy the buffers */
709 newbuf = gst_buffer_new_and_alloc (len);
711 /* copy the first buffer's data across */
712 memcpy (newbuf->data, buf1->data + offset, buf1->size - offset);
713 /* copy the second buffer's data across */
714 memcpy (newbuf->data + (buf1->size - offset), buf2->data,
715 len - (buf1->size - offset));
717 /* if the offset is 0, the new buffer has the same timestamp as buf1 */
719 GST_BUFFER_OFFSET (newbuf) = GST_BUFFER_OFFSET (buf1);
720 GST_BUFFER_TIMESTAMP (newbuf) = GST_BUFFER_TIMESTAMP (buf1);
722 /* if we completely merged the two buffers (appended), we can
723 * calculate the duration too. Also make sure we's not messing with
724 * invalid DURATIONS */
725 if (buf1->size + buf2->size == len) {
726 if (GST_BUFFER_DURATION_IS_VALID (buf1) &&
727 GST_BUFFER_DURATION_IS_VALID (buf2)) {
729 GST_BUFFER_DURATION (newbuf) = GST_BUFFER_DURATION (buf1) +
730 GST_BUFFER_DURATION (buf2);
732 if (GST_BUFFER_OFFSET_END_IS_VALID (buf2)) {
734 GST_BUFFER_OFFSET_END (newbuf) = GST_BUFFER_OFFSET_END (buf2);